Umbrella without a positioning bow spring

ABSTRACT

The present invention relates to an umbrella without a bow spring provided in a shaft of the umbrella. The improved umbrella is provided a special umbrella frame accompanying with a runner provided around the shaft. While the umbrella is opened, there will be an upward force acting on the runner for maintaining the umbrella in opened state. So it is unnecessary to provide a bow spring in the shaft and obtains utilized effect.

BACKGROUND OF THE INVENTION

[0001] A conventional foldable umbrella is always provided with a bow spring in a shaft to stop a runner for keeping the umbrella being opened. This known structure is more trouble in manufacturing and cost high. Moreover, the shaft must be provided with a gap for receiving the bow spring that may reduce the strength of the shaft and will be not utilized.

[0002] Accordingly, the primary object of the invention is to provide an umbrella, which does not need a bow spring provided in the shaft. With a special frame, the umbrella can be maintained in opened state for improvement. Now the features and advantages of the present invention will be described in detail with reference to the accompanying drawings.

BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS

[0003]FIG. 1 is a plan view showing a foldable umbrella at incomplete opened state according to the present invention.

[0004]FIG. 2 is a plan view showing the foldable umbrella at complete opened state according to the present invention.

[0005]FIG. 3 is an analysis drawing showing the reacting force of the opened foldable umbrella according to the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0006] Please refer to FIGS. 1 and 2 first, the present invention includes a shaft (1) having an upper joint (11). A runner (2) is provided around the shaft (1) slidably. The frame (3) has ribs to connect with the upper joint (11) and the runner (2) to become a normal foldable umbrella. The characteristic of the present invention is that the frame (3) includes a first rib (31), a second rib (32), a third rib (33), a fourth rib (34), and a tail rib (35). The said first rib (31) has its inner end to connect with the upper joint (11) and its outer end to connect with middle position of the second rib (32). The second rib (32) has its inner end to connect with the runner (2) and its outer end to connect with an inner position of the third rib (33). A first branch rib (36) is provided between outer position of the first rib (31) and inner end of the third rib (33). The third rib (33) has its outer end to connect with inner position of the fourth rib (34). An arched elastic rib (37) is provided between outer position of the second rib (32) and inner end of the fourth rib (34) under the third rib (33). The fourth rib (34) has its outer end to connect with inner position of the tail rib (35). A second branch rib (38) is provided between outer position of the third rib (33) and inner end of the tail rib (35).

[0007] Please refer to FIG. 3, provided connecting point of inner end of the second rib (32) and the runner (2) is O, connecting point of outer end of the second rib (32) and the third rib (33) is B, connecting point of the first rib (31) and the upper joint (11) is E, connecting point of the first rib (31) and the second rib (32) is A, connecting point of the first rib (31) and the first branch rib (36) is C, connecting point of the third rib (33) and the first branch rib (36) is D. It will be found that the total length of EC, CD, and DB will be larger than the length of OB.

[0008] When opening the umbrella, since the total length of EC, CD, and DB is larger than the length of OB, the outer portion of the second rib (32) will be downward inclined. Base of the pressure of the whole umbrella frame, there will be a force F on the runner (2) and the force F may occur an upward partial force f to keep the umbrella in opened state without a conventional positioning structure, such as a bow spring in the shaft. When to close the umbrella, it will be very easy to pull the runner (2) with a downward force being larger than the partial force f.

[0009] Accordingly, the invented assembly of the present invention obviously obtains utility and improvement. It should be allowed for patent and is applied. 

What is claimed is:
 1. An umbrella without a bow spring including a shaft having an upper joint, a runner provided around the shaft slidably, and frame having ribs to connect with the upper joint and the runner to become a normal foldable umbrella; the characteristic is that the frame including a first rib, a second rib, a third rib, a fourth rib, and a tail rib, wherein the said first rib having its inner end to connect with the upper joint and its outer end to connect with middle position of the second rib, the second rib having its inner end to connect with the runner and its outer end to connect with an inner position of the third rib, and a first branch rib being provided between outer position of the first rib and inner end of the third rib. 